The characterisation of multiphase flow properties is essential for predicting large-scale fluid behaviour in the subsurface. Insufficient representation of small-scale heterogeneities has been identified as a major gap in conventional reservoir simulation workflows. Capillary heterogeneity has an important impact on small-scale flow and is one of the leading causes of anisotropy and flow rate dependency in relative permeability. We evaluate the workflow developed by Jackson et al. (2018) for use on rocks with complex heterogeneities. The workflow characterises capillary heterogeneity at the millimetre scale. The method is a numerical history match of a coreflood experiment with the 3D saturation distribution as a matching target and the capillary pressure characteristics as a fitting parameter. Coreflood experimental datasets of five rock cores with distinct heterogeneities were analysed: two sandstones and three carbonates. The sandstones exhibit laminar heterogeneities. The carbonates have isotropic heterogeneities at a range of length scales. We found that the success of the workflow is primarily governed by the extent to which heterogeneous structures are resolved in the X-ray imagery. The performance of the characterisation workflow systematically improved with increasing characteristic length scales of heterogeneities. Using the validated models, we investigated the flow rate dependency of the upscaled relative permeability. The findings showed that the isotropic heterogeneity in the carbonate samples resulted in non-monotonic behaviour; initially the relative permeability increased, and then subsequently decreased with increasing flow rate. The work underscores the importance of capturing small-scale heterogeneities in characterising subsurface fluid flows, as well as the challenges in doing so.

Groundwater is critical in sustaining streamflow, especially in mountain catchments, because of its ability to supply baseflow in the absence of precipitation. In water-limited arid and semi-arid mountain environments, the need to characterize groundwater recharge and discharge has grown in tandem with demands to effectively manage current and future water resources. However, studying groundwater is challenging in complex terrain due to limited field measurements. Nearly a decade of monitoring data collection at Gordon Gulch in the Colorado Front Range provides a unique opportunity to study such an environment. The field data is used to parameterize and calibrate a groundwater flow model (MODFLOW-NWT). Model results reveal spatial and temporal patterns in groundwater recharge and discharge to the stream. Groundwater is recharged primarily by one to two recharge events each year, driven by spring snowmelt and rain. The majority of groundwater recharge occurs in upper Gordon Gulch and is stored in saprolite and weathered bedrock. Groundwater is discharged to the stream via long, deep flowpaths sourced from upper Gordon Gulch and short, shallow flowpaths from soil and saprolite in lower Gordon Gulch. Using Gordon Gulch as a case study, this model and data analysis contribute to a larger effort to understand and constrain the mechanisms driving groundwater recharge and groundwater-stream exchanges in semi-arid, montane environments.

Seismic history of the Mosha fault, the most important active fault of Eastern Tehran metropolis, and its relation to the activity of Damavand Volcano, the highest mountain of the Middle-East, is investigated. Historical earthquakes cover the three segments of the Mosha fault by three 6.5

Most of Earth’s volcanic eruptions occur underwater, and these submarine eruptions can significantly impact large-scale earth systems. In this study, we develop a new semi-automated analysis framework to detect submarine eruptions through the supervised classification of satellite images on Google Earth Engine (GEE). We present a case study from the Rabaul caldera region in Papua New Guinea and find a large number of new unreported pumice rafts (in ~16% of images from 2017–present). After analysis of the spatial pattern of raft sightings and ancillary observations, we interpret that these rafts are not the result of a new eruption. Instead, we posit that the observed rafts represent remobilization of pumice clasts from previous historical eruptions. This novel process of raft remobilization may be common at near-shore/partially submarine caldera systems (e.g., Rabaul, Krakatau) and has significant implications for new submarine eruption detection, volcanic stratigraphy, and biological dispersal by rafts.

Krypton-81 dating provides new insights into the timing, mechanisms, and extent of meteoric flushing versus retention of saline fluids in the subsurface in response to changes in geologic and/or climatic forcings over 50 ka to 1.2 Ma year timescales. Remnant Paleozoic seawater-derived brines (2-2.5 km depth) associated with evaporites in the Paradox Basin, Colorado Plateau, are beyond the 81Kr dating range (>1.2 Ma) and have likely been preserved due to negative fluid buoyancy and low permeability. 81Kr dating of formation waters above the evaporites indicates topographically-driven meteoric recharge (0.03-0.8 Ma) and salt dissolution since the Late Pleistocene. Formation waters below the evaporites, in basal aquifers, contain relatively young meteoric water components (0.4-1.1 Ma based on 81Kr) that partially flushed remnant brines and dissolved evaporites. We demonstrate that recent, rapid denudation of the Colorado Plateau (<4-10 Ma) activated deep, basinal-scale flow systems as recorded in 81Kr groundwater age distributions.

The Cameroon Volcanic Line (CVL) is a linear feature of volcanism that begins off the western coast of Africa with several islands and continues on shore through Cameroon further into the African continent. Equatorial Guinea’s Bioko Island is the largest and last of the CVL volcanic islands. It is home to three shield volcanoes: Pico de Basile, Pico Biao, and Gran Caldera de Luba. Eruptive history is only known for Pico de Basile which erupted within the past 100 years, and steam vents were observed as recently as 2012. There is no permanent seismic monitoring; the closest seismic stations are in Cameroon and have not reported data since 2015. The CVL is of scientific interest and has been studied by several groups. Most geophysical studies focus on the area around Mt. Cameroon, the most active volcano in the system. A network of seismic stations was installed across the entire country from 2005-2007. There has been no successful geophysical surveys of the island portion of the line. In Nov-2017 Drexel University, supported by the Bioko Biodiversity Protection Program (BBPP) and the Universidad Nacional de Guinea Ecuatorial (UNGE), installed 4 broadband seismometers on Bioko. Two stations were installed in March of 2019.Preliminary earthquake detection and location was completed with an automated STA/LTA algorithm. Initial locations use the global IASP91 model and events were relocated with a local model. Events cluster in two areas: those near Bioko Island and those near Cameroon. Between 12-Dec-2017 and 17-Feb-2018, 77 events were recorded. Local magnitudes range between 0.16and 2.61. Of these events, 49 are located near Cameroon and 28 are near Bioko. Most of the depths are upper to mid-crust. Analysis of the entire data set yields 458 events with 367 near Bioko Island and 91 near Cameroon. The range in local magnitude is -0.28 – 3.86. Our preliminary results show seismicity associated with Bioko Island as well as Cameroon. Locations match well with events recorded by the regional network previously installed in Cameroon. In addition, the rate of seismicity recorded from2017-2019 is comparable to what was observed from the Cameroon network when distance is taken into account. Data has been retrieved in Feb-2018, Nov-2018, and Mar-2019. The next service was scheduled Mar-2020 but the trip was canceled due to travel restrictions.

Notwithstanding the large number of studies on bedforms such as dunes and antidunes, performing quantitative predictions of bedform type and geometry remains an open problem. Here we present the results of laboratory experiments specifically designed to study how sediment supply and caliber may impact equilibrium bedform type and geometry in the upper regime. Experiments were performed in a sediment feed flume with flow rates varying between 5 l/s and 30 l/s, sand supply rates varying between 0.6 kg/min and 20 kg/min, uniform and non-uniform sediment grain sizes with geometric mean diameter varying between 0.22 mm and 0.87 mm. The experimental data and the comparison with datasets available in the literature revealed that the ratio of the volume transport of sediment to the volume transport of water Qs/Qw plays a prime control on the equilibrium bed configuration. The equilibrium bed configuration transitions from washed out dunes (lower regime), to downstream migrating antidunes (upper regime) for Qs/Qw between 0.0003 and 0.0007. For values of Qs/Qw greater than those typical of downstream migrating antidunes, the bedform wavelength increases with Qs/Qw. At these high values of Qs/Qw equilibrium bed configurations with fine sand are characterized by upstream migrating antidunes or cyclic steps, and significant suspended load. In experiments with coarse sand, equilibrium is characterized by plane bed with bedload transport in sheet flow mode. Standing waves form at the transition between downstream migrating antidunes and bed configurations with upstream migrating bedforms.

The multiscale analysis of fracture patterns helps to define the geometric scaling laws and the genetic relationships correlating outcrop- and regional-scale structures in a fracture network. Here we present the results of the multiscale analysis of the geometrical and spatial organization properties of the fracture network affecting the Rolvsnes granodiorite of the crystalline basement of southwestern Norway (Bømlo island). The fracture network shows a spatial distribution described by a fractal dimension D ≈ 1.51, with fracture lengths distributed following a power-law scaling law (exponent α = -1.95). However, orientation-dependent analyses show that the identified fracture sets vary their relative abundance and spatial organization with scale, defining a hierarchical network. Fracture length, density, and intensity of each set vary following power-law scaling laws characterized by their own exponents. Comparing the results from each set with those generated from the entire network, we discuss how the obtained scaling laws improve the accuracy of resolving sub-seismic-resolution scale structures, which steer the local-scale permeability of fractured reservoirs. As documented in the field, the identified fracture sets affect the fractured basement permeability differently. Thus, results of multiscale, orientation-dependent statistical analyses, integrated with field analyses of fracture lineaments, can effectively improve the detail and accuracy of permeability prediction of fractured reservoirs. Our results show also how regional geology and analytical biases affect the results of multiscale analyses and how they must be critically assessed before extrapolating the conclusions to any other similar case study of fractured unconventional geofluids reservoirs.

Using web standards including Schema.org and JSON-LD, the GeoCODES project extends Schema.org with Project 418's geoscience specific vocabulary. By embedding properly formatted and populated JSON-LD files in web sites serving geolocated datasets, search engines such as Google and Bing are able to parse and index these data sets and then to provide information concerning these datasets via standard web search tools. Due to the difficult nature of properly formatting and populating these JSON-LD structures, the GeoCODES User Interface was created to guide data providers through the process of describing the data and validating the descriptions against standard vocabularies. The result is user friendly and easily extensible web based, mobile device ready tool for automatically generating JSON-LD metadata for organizations and datasets. This ultimately allows the original data to be found and used by both scientists and the public.

Many of the world’s major aquifers are under severe stress as a result of intensive pumping in support of irrigated agriculture. The question of what the future holds for these aquifers and the agricultural production they support is of paramount importance in a world of burgeoning populations, dietary shifts, and climate change. Addressing that question requires a better understanding of the how and why of a particular aquifer’s response to pumping. One important, but largely underutilized, source of information is the data from monitoring well networks that provide near-continuous records of water levels through time. Although many regions have such networks operated by local, state, or Federal entities, the vast majority of efforts are, by fiscal necessity, focused on keeping the networks up and running. Little, if any, time is spent on interpreting the acquired hydrographs. The index well network in the High Plains aquifer (HPA) in central and western Kansas is an exception, as hydrograph interpretation is an important program emphasis. Examination of multiyear hydrographs has resulted in the development of profound insights concerning, for example, the frequency of episodic recharge, the magnitude and variability of net inflow, characteristics of the monitored aquifer (continuity, hydraulic regime, etc.), and the impact of extreme meteorological events. These insights have allowed us to develop a significantly better understanding of how the aquifer will respond to proposed management actions; such an understanding is critical for charting more sustainable paths for aquifers across the globe. We will demonstrate these points through an examination of two multiyear hydrographs from the HPA in western Kansas with an emphasis on the insights that shed light on the prospects for the sustainability of this heavily stressed system and the agricultural production that it supports.

To characterize how moderately large impactors might alter the differentiation and internal structure of Mars, we examine the fractional crystallization of intermediate depth magma oceans, and document that residual liquids ultimately become denser than normal Martian mantle, establishing unstable density gradients and inducing extensive magma descent within an evolving Mars. Fractional crystallization of intermediate depth magma oceans on Mars is likely to produce liquids that are dense enough to descend to the core-mantle boundary (CMB) and thus form a stably stratified thermochemical boundary layer at the Martian CMB. If this layer cooled sufficiently to crystallize, its mineralogy would be dominated by garnet and ferropericlase, or stishovite and ringwoodite, with changes in the descending liquid’s bulk composition having relatively minor effects on the resulting phase assemblage. While the size of Mars’ core remains uncertain, the addition of such a thermal boundary layer would impede the stabilization of (Mg, Fe)SiO3-perovskite at depth in Mars, although it would contain modest amounts of CaSiO3-perovskite. Such a compositionally distinct thermal boundary layer at the base of the Martian mantle would substantially elevate the inferred temperature of the Martian core, and also produce markedly lowered heat flow at the top of its core, with a potentially causal relation with the current lack of an internally generated Martian magnetic field. We calculate the seismic velocity anomalies that would be expected to be associated with such a layer, and find that the shift in mineralogy at depth should produce a seismic discontinuity that could prospectively be detectable by Martian seismic deployments.

Large Igneous Provinces (LIPs) are among the greatest magmatic events in Earth history withvolumes in excess of ∼500,000 km3 of predominantly basaltic lavas covering hugecontinental and ocean regions (>100,000 km2). Field observations suggest that lava flowfields in LIPs are made largely of sheet pāhoehoe lava lobes and the 10-100 m thick flows areformed by inflation. Understanding the emplacement history of these lava lobes can help usinfer the magnitude and temporal dynamics of past events.We use a phase-field model to describe solidification and re-melting of sequentially emplacedlava flows. We calibrate model parameters using field measurements at Makaopuhi lava lakeand perform extensive numerical simulations by varying the thickness of individual flow and thetime intervals between eruptions. These results help quantify the complex interplay betweenthermal evolution, flow thickness and emplacement frequency. If flows are thick enough andthe interval between emplacement short enough, reheating and re-melting may remove thetextural record of flow contacts – making flows appear thicker than they actually were. Guidedby field observations in Columbia River Basalt and Deccan Traps, we illustrate how the finalmorphology of sequentially emplaced lava is controlled by both the time scale of emplacementintervals and the time scale of cooling. We summarize our results to provide theoreticalconstraints on the thickness and emplacement intervals of individual LIP lava flows.

The formation of fluvial dunes has been usually investigated assuming an infinite availability of the mobile sediment. Field observations and laboratory experiments nevertheless indicate that the volume of sediment available for transport affects their morphology. Here we undertake a stability analysis showing the formation of small amplitude sand dunes in steady currents accounting for the effects of sediment starvation on their formative mechanisms and compare it against laboratory experiments and an application of a fully numerical commercial model of finite amplitude dunes, thus enabling an improved understanding of the genesis of starved fluvial dunes. Both small and finite amplitude dunes are shown to be affected by sediment starvation. As their growth progressively exposes a motionless substratum, both models predict the lengthening of starved dunes with increasing irregularity in their spacing. These findings conform with the outcome of physical experiments performed in a laboratory flume and existing measurements of starved fluvial dunes in the field.

During its late-stage evolution, the European Alpine orogen witnessed a northwest-directed propagation of its deformation front along an evaporitic basal décollement into the foreland. This resulted in the decoupling of the northern Alpine Molasse Basin from its basement and the formation of the Jura fold-and-thrust belt. Here, we present the first absolute age and temperature constraints on deformation along this basal décollement using combined carbonate U-Pb LA-ICP-MS dating and clumped isotope thermometry. We analyzed calcite veins associated with a thrust fault branching off from the basal décollement in the distal Molasse Basin and slickenfibers from thrusts and strike-slip faults in the eastern Jura Mountains. Our U-Pb data provide evidence for tectonic activity related to Alpine contraction in this region between ~14.5 Ma and ~4.5 Ma ago. Accordingly, the propagation of Alpine deformation into the distal foreland along the basal décollement occurred earlier than commonly inferred by biostratigraphy, at Middle Miocene (Langhian) times at the latest. Younger deformation ages between ~11.5 and ~4.5 Ma correspond very well in time with shortening in the Subalpine Molasse and the Central Alps proving simultaneous tectonic activity along both thrust fronts; e.g. the Jura Mountains and the Subalpine Molasse. Clumped isotopes reveal vein calcite precipitation at temperatures between 53 and 104 °C from fluids with oxygen isotope compositions between -6.2 and +9.5 ‰. Our data show that the burial conditions in the studied area remained constant between ~14.5 Ma and ~4.5 Ma indicating that the previously reported large-scale foreland erosion initiated after ~4.5 Ma.

Coseismic landslides are a major hazard associated with large earthquakes in mountainous regions. Despite growing evidence for their widespread impacts and persistence, current understanding of the evolution of landsliding over time after large earthquakes, the hazard that these landslides pose, and their role in the mountain sediment cascade remains limited. To address this, we present the first systematic multi-temporal landslide inventory to span the full rupture area of a large continental earthquake across the pre-, co-and post-seismic periods. We focus on the 3.5 years since the 2015 Mw 7.8 Gorkha earthquake in Nepal and show that throughout this period both the number and area of mapped landslides have remained higher than on the day of the earthquake itself. We document systematic upslope and northward shifts in the density of landsliding through time. Areas where landslides have persisted tend to cluster in space, but those areas that have returned to pre-earthquake conditions are more dispersed. Whilst both pre-and coseismic landslide locations tend to experience persistent post-earthquake landsliding, a wider population of newly activated but spatially-dispersed landslides has developed after the earthquake. This is particularly important for post-earthquake recovery plans that are typically based on hazard assessments conducted immediately post-earthquake and thus do not consider the evolving landslide hazard. We show that recovery back to pre-earthquake landsliding rates is fundamentally dependent on how that recovery is defined and measured. Clarity around this definition is particularly important for informing a comprehensive and precautionary approach to post-earthquake landslide hazard and risk.

We quantify how changes in natural flood discharge control bedload rest time distributions and may influence particle diffusion through mountain river networks. We embedded accelerometers and gyroscopes into artificial cobbles deployed in Halfmoon Creek, Colorado, USA, and measured bedload transport during 28 daily snowmelt flood hydrographs in 2015. From the motion sensor data we calculate motion and rest distributions over ~6 orders of temporal magnitude, from ~2 seconds to ~1 month. Motion durations follow a thin-tailed exponential distribution. Rests >12 hours can be well fit by both truncated Pareto distributions and exponentially-tempered Pareto distributions, suggesting ambiguity in whether rests remain heavy-tailed or transition to thin tails at even longer timescales. Rest time scaling varies not only with timescale but also with flow intensity, becoming less heavy-tailed as shear stress increases. A rest time scaling break at ~12 hours may be caused by daily discharge cyclicity.

Mesozoic subduction of the Paleo-Pacific Plate triggered intense tectonism, magmatism, and metallogeny in the eastern South China Block (E-SCB) and set off long-term tectonic, topographic, and climatic responses. However, contrasting hypotheses have been proposed to interpret the timing, style, and evolution of this oceanic subduction. Unraveling the exhumation history of the E-SCB is crucial to understanding deep subduction processes. To address the poorly documented exhumation history of the E-SCB, we present first zircon and apatite (U-Th)/He dates from eight Mesozoic granitoids distributed in a lateral profile across the intracontinental E-SCB. These data are combined with a compilation of regional thermochronological data, in order to address the evolution of the E-SCB in a tectonic, topographic, and climatic evolution framework. Zircon and apatite (U-Th)/He central ages of the investigated plutons range from 146–30 Ma and 82–31 Ma, respectively, implying long-lived exhumation of the intracontinental E-SCB. Inverse thermal modelling indicates the intracontinental SCB underwent multi-phase exhumation events from the Jurassic, despite variable onset timing and the fact that the far intracontinental E-SCB had been an exhumation center prior to the Early Cretaceous. In addition, a compilation map of regional thermochronological data reveals propagation of the exhumation center from the intracontinental to the epicontinental E-SCB over time (from the Cretaceous to the Paleogene). Based on these results, we propose a refined model of Paleo-Pacific Plate subduction since the Triassic. This model is in good agreement with geological observations in the E-SCB and capable of explaining regional magmatism, metallogeny, tectonism, and exhumation.

Zircon Raman dating is an emergent thermochronological method. It exploits the disruption of the zircon lattice due to α-disintegration of trace amounts of 238U, 235U, 232Th, and their daughters. The radiation damage broadens the Raman bands and shifts them to lower wavenumbers. The Raman bandwidths provide a sensitive measure for the accumulated lattice damage (Nasdala et al., 1995; Nasdala et al., 2001). The measured bandwidth and the effective uranium concentration define the Raman age (Härtel et al., 2021). Radiation damage anneals upon heating and the meaning of the Raman age depends on the zircon’s thermal history. The Raman age is a formation age if no annealing has taken place, or a reset age if all pre-existing damage has been annealed by a geological heating event. In the case of partial annealing, however, the Raman age is a mixed age with no obvious geological significance. Mixed ages are difficult to interpret and cannot be distinguished from reset ages using the standard procedure for annealing detection (Nasdala et al., 2001). On the other hand, inhomogeneous damage distributions due to actinide zoning within zircon grains present a problem for zircon Raman dating. Overlapping signals from more and less damaged zones lead to asymmetric Raman bands and overestimated bandwidths (Nasdala et al., 2005). We discuss Raman spectra of zircon from partially annealed samples and spectra with asymmetric bands. We introduce discrimination plots based on the 356, 439, and 1008 cm-1 bandwidths that provide a means for detecting and distinguishing asymmetry and partial annealing. We discuss examples of zircon Raman dating and present a measurement protocol.

A compilation of legacy and new low-temperature thermochronological data from the British-Irish Isles and their surrounding offshore shelves yielded c. 700 AFT ages and c. 180 AHe ages from 29 peer-reviewed papers, 27 Geotrack industry reports and several new unpublished studies from offshore Ireland. The compilation shows for the first time a regional age pattern, with older AFT ages in Scotland and Northern Ireland than in the rest of Ireland. This pattern is tentatively attributed to the influence of the Anton-Dohrn Transfer Zone (ADTZ) during an Early Cretaceous phase of plate-wide uplift that resulted in more exhumation to the SW of the transfer zone than to the NE. Caledonian faults might also create differential exhumation of the tectonic blocks between them, as is observed in the compilation of AFT data from northern Scotland and this could explain the dispersion in the timing of exhumation seen on the North Porcupine High, offshore Ireland. Finally, the Paleogene exhumation visible in the Central Irish Sea, and attributed in recent years to igneous underplating, has not been detected in the Malin Sea-Outer Hebrides, despite the area being underlain by a high-velocity body also interpreted as igneous underplating. In conclusion, a detailed analysis of a large dataset of low-temperature thermochronological has revealed the possible influence of major crustal structure on the Mesozoic exhumation of this part of the NE Atlantic Margin, with large-scale decoupling occurring at a transfer zone and medium-scale decoupling occurring along regional-scale faults. The dataset also shed some doubts on the generic nature of exhumation caused by igneous underplating which has been much discussed in recent years.

Organic matter is an important constituent in organic-rich shale, which influences the hydrocarbon generation, as well as the mechanical behavior, of shale reservoirs. The physical, chemical, and mechanical properties of organic matter depend on the source material and the thermal evolution process. Previous works attempted to investigate the impact of thermal maturation on the mechanical properties of organic matter. However, owing to the lack of maceral classification and the limitation of data volume during the mechanical measurement, no consistent trend has been identified. In this work, vitrinite reflectance test, scanning electron microscope observation, nanoindentation, and micro-Raman analysis were combined for geochemical and mechanical characterization. A total of 114 test areas were selected for testing, enhancing reliability of the test results. The Young’s moduli of organic matter are from 3.57 GPa to 8.32 GPa. With the same thermal maturity, inertinite has the highest Young’s modulus, while the modulus of bitumen is the lowest. The Young’s moduli of different organic types all increase with vitrinite reflectance. When vitrinite reflectance increases from 0.62% to 1.13%, the modulus of inertinite and vitrinite is increased by 57% and 78%, respectively. In addition, with the increase of thermal maturity, the micro-Raman test results show a decrease of intensity ratio of D peak to G peak, indicating an increase of the ordered structure in organic matter. Organic type and thermal maturity reflect the diversity of the source material and chemical structure change during the thermal evolution process, and together they influence the mechanical properties of organic matter.

In order to explore the cause behind a recently so-called inversion of activation energy between dislocation-diffusion creep, we compress Fangshan dolomite at effective pressures of 50-300 MPa, temperatures of 27-900 ℃, and strain rates of 10-2×10 s using a Paterson-type apparatus. Two end-member deformation regimes, each with respective diagnostic flow law and microstructure, are recognized. At T≤500 ℃, low temperature plasticity (LTP), expressed by an exponential constitutive equation with and , was determined with weakly strain rate dependence and thermal hardening of the strength, and microstructures of predominant undulatory extinctions or f-twinning (Regime 1). At T≥800 ℃, dislocation creep, described by a power law equation ( with , and ), was defined with significant strain rate and temperature sensitivities of strength, and microstructures dominated by smooth undulating extinction and new recrystallized grains (Regime 2). Regime 3, transition from LTP to dislocation creep, is also recognized from ~600 ℃ to 800 ℃ with strain rate dependence of strength changing with temperature and developing microstructures similar to those of regime 2. Overall the medium-grained Fangshan dolomites show similar rheology to coarse-grained Madoc dolomites but a beginning temperature of regime 2 about 50-100 ℃ than the latter, making the dislocation creep of Fangshan dolomite clearly recognized under the condition that dolomite decomposition has no obvious effect. Extrapolated to nature, dislocation creep is expected to occur in a relatively narrow space undergoing high temperatures and relatively high stresses, instead diffusion creep is expected to dominate the deformation of dolomite in low stress tectonic settings.

Does life currently exist, or did life once exist, on other worlds in our solar system? The proximity of the rocky planets of our solar system, Venus and Mars, make them obvious targets for the first attempts to answer these questions via direct exploration, with concomitant implications for, and input to, how we think of exoplanets. Given the limited resources we have to explore our neighbors in space, an ecological assessment (based on terrestrial ecosystem principles) might help us target our search and methodology. Studies of extreme life on Earth consistently reveal adaptability. Mars has been the target of many life-related investigations [1, many others]. Venus has not, yet there may be compelling reasons to think about extant life on the second planet [2], and lessons to learn there about searching for life elsewhere in the solar system and beyond. The Venus Life Equation: Venus may have been habitable for billions of years its history and may still be habitable today. Our current state of knowledge of the past climate of Venus suggests that the planet may have had an extended period – perhaps 1-2 billion years – where a water ocean and a land ocean interface could have existed on the surface, in conditions possibly resembling those of Archaean Earth [3]. At present, Venus’ surface is not hospitable to life as we know it, but there is a zone of the Venus middle atmosphere, ~55 km altitude, just above the sulfuric acid cloud layer, where the combination of pressure, temperature, and gas-mix are more Earth-like than anywhere else in the solar system [2, 4]. The question of whether life could have – or could still – exist on the Earth’s closest neighbor is more open today than it’s ever been. Here we approach the question of present-day life on Venus in a manner analogous to the Drake Equation [5], treating the possibility of current Venus life as an exercise in informal probability – seeking qualitatively the likelihood or chance of the answer being nonzero.The working version of the Venus Life Equation is expressed as: L = O * R * A where L is the likelihood (zero to 1) of there being life on Venus in the present-day, O (origination) is the chance life ever began and “broke out” on Venus, R (robustness) is the potential current and historical size of diversity of the Venus biosphere, A (acceptability) is the chance that conditions amenable to live persisted spatially and temporally to the present. The Venus Life Equation is a work-in-progress as a pre-decadal White Paper [6] and its variables are currently being refined. [1] McKay 1997, Springer, Dordrecht, 1997. 263-289. [2] Limaye et al. 2018 Astrobiology, 18(9), 1181-1198. [3] Way et al. 2016 JGR 43(16) 8376-8383. [4] Schulz-Makuch et al. 2004 Astrobiology 4, 11-18. [5] Burchell 2006, Int. J. Astrobio, 5(3) 243-250. [6] Izenberg et al. 2020, https://is.gd/vd4JE7 (location of Latest version of Venus Life Equation White Paper).

The surface of Ganymede is characterized by dark and light terrains. Light terrain, covering two thirds of the surface, is retained to be younger and resulted from resurfacing events, likely correlated to a global expansion of Ganymede [1]. It is typically characterized by several sets of subparallel troughs and ridges, called grooves. They highly modify the dark terrain and the other pre-existing features. Since these areas display two different superposed spacing scales, grooves have been interpreted as the product of extensional tectonism [2] and two different faulting styles have been recognized (horst-graben and domino) [3]. Nevertheless, the stratigraphical relationship, the required conditions to the grooves’ origin and the tectonic mechanisms are still objects of debate. In preparation of the ESA Juice Mission, we are producing DEMs of extended areas of the surface of Ganymede, using both Galileo and Voyager imagery. We use the open-source suite of tools NASA Ames Stereo Pipeline (ASP) [4], by using the photoclinometry-based “shape-from-shading” (SfS) tool. Since SfS needs an input DEM generated preferably with stereo images, and we do not have such data in this area of Ganymede, we used the methodology proposed by Lesage et al. 2021 [5]. Figure 1 shows an example of Digital Elevation Model using a Galileo image (EDR 2878r, with a resolution of 151 m/px) of Anshar Sulcus (167.40° E, 11.50° N). The DEM clearly shows the height variations of the ridge and trough systems included in the study area. These novel Digital Elevation Models can provide new insights on the geological processes of Ganymede. Acknowledgments GM acknowledges support from the Italian Space Agency (contract ASI/2018-25-HH.0). References [1] Pappalardo R.T., et al., 2004. Jupiter: The Planet, Satellites and Magnetosphere, 2:363. [2] Prockter L.M. et al.,2010. Space Sci Rev 153:63-111 [3] Pizzi A. et al., 2017. Icarus 288: 148-159 [4] Beyer, R. A. et al., (2018), Science, 5. [5] Lesage E. et al. (2021), Icarus, 114373.

Cyanobacterial Harmful Algal Blooms (CyanoHABs) are progressively becoming a major water quality and public health hazard worldwide. Untreated CyanoHABs can severely affect human health due to their toxin producing ability, causing physiological and neurological disorders such as non-alcoholic liver disease, dementia to name a few. Transfer of these cyanotoxins via food-chain only accelerates public health hazards. CyanoHABs can potentially also lead to a decline in aquatic and animal life, hampering recreational activities at waterbodies and ultimately affecting the country’s economy gravely. CyanoHABs require nutrient rich warm aquatic environments to bloom and their proliferation in increasingly warmer areas of the world can be an indirect indicator of global climate change. Many lakes in the United States have been experiencing such CyanoHABs in the summers, which only grow severe every coming year, and this is consistently leading to increased public health implications. A recent study (September, 2021) by the Centre for Disease Control quantified hospital visits with the trend of such CyanoHABs to indeed observe a strong correlation between the two. This necessitates a need for a user-friendly and accessible infrastructure to monitor inland and coastal waterbodies throughout the U.S for such blooms. We present a remote sensing-based approach wrapped in a lucid web-app, “CyanoTRACKER”, which can help detect CyanoHABs on a global level and act as an early warning system, potentially preventing/lessening public health implications. CyanoHABs are dominated by the Phycocyanin pigment, which absorbs sunlight strongly around 620 nm wavelength. Owing to this specific absorption characteristic and the availability of a satellite band at exactly 620 nm, we use the opensource Sentinel-3 OLCI satellite data to detect the presence of CyanoHABs. CyanoTracker is a user-friendly Google Earth Engine dashboard, which is easily accessible via only a browser and an internet connection and allows for a variety of near-daily analysis options such as: a) select any location throughout the world and view satellite image based on date-range of choice, b) click on any pixel in the satellite image and detect presence/absence of cyanobacteria, c) visualize the spatial spread as well as the temporal phenology of an ongoing bloom or a potential incoming bloom. This dashboard is easily accessible to water-managers and in fact, anyone who wishes to use it with minimal training and can effectively serve as an early warning system to CyanoHAB induced disease outbreaks.